Air pressure monitors are used to monitor the air pressure within conventional pneumatic tires to attain peak performance of the vehicle in terms of safety, optimum handling, and maximum gas mileage. If the vehicle operator is aware that a conventional tire has less than optimum air pressure the vehicle operator is more inclined to maintain the optimum or proper air pressure to maximize vehicle performance.
In the prior art, an air pressure monitor for monitoring the air pressure within pneumatic tires includes a pressure sensor and a wireless transmitter coupled to the pressure sensor. The wireless transmitter may transmit a unique identification code associated with each tire to identify the tire. In order to fully identify the relationship between the identification codes and the corresponding mounting positions of the tires, a person (e.g., a service technician) must manually enter or recalibrate the proper relationship at the time when the tires are mounted on their respective positions on the vehicle. Accordingly, if the tires are rotated, as is customary with ordinary vehicle service to provide uniform tread wear, the correspondence between the identification codes and the mounting positions must be recalibrated to identify the air pressure in the correct tires. Thus, a need exists for an air pressure monitor that automatically updates the identification code associated with each tire after mounting the tire or rotating the tire.
During the last decade, advances have been made in the construction of tires. For example, run-flat tires have become a relatively commonplace feature for luxury automobiles. A run-flat tire is capable of operation when air pressure is low or substantially reduced because of the puncture or another fault in the tire. Run-flat tires allow a vehicle to be driven a moderate distance such that a vehicle operator can seek repair of a defective tire with greater convenience than otherwise possible. The use of run-flat tires may also facilitate size reduction in vehicles because the spare tire may be eliminated if a vehicle is equipped with run-flat tires.
A vehicle operator may be unaware that a run-flat tire has lost its air pressure from visual inspection because of the construction of the run-flat tire. The run-flat tire generally handles adequately and is greatly superior in handling characteristics in comparison to a conventional flat tire that has lost air pressure. However, a vehicle operator may be unaware in the deterioration of the handling characteristics of a vehicle due to the loss of air pressure in the run-flat tire. Thus, there is a need for an air pressure monitor for monitoring the air pressure of run-flat tires to notify the driver of the lost air pressure so that the vehicle operator can seek appropriate maintenance and repair.